Intercept Geometry: Table of Contents
- Part I: Introduction
- Part II: Definitions
- Part III: Target Aspect & Lateral Separation
- Part IV: Modern Gameplans (P-825/17)
- Part V: P-825/17: DT, CT, Timeline
- Part VI: Modern Intercept Demo Videos (P-825/17)
- Part VII: 2000s Intercepts (P-825/02)
- Part VIII: Intercept Progression & Lead Collision (P-825/02)
- Part IX: “Unknown Procedures” & Fleet Conversions p1 (P-825/02)
- Part X: Fleet Conversions p2 & Advanced Intercepts (P-825/02)
- Part XII: In-Depth Timeline (from “Picture” to “Crank”)
- Part XIII: In-Depth Timeline (continuation: FOX 3/1/2)
- Part XIV: Crews’ take on Timelines for DCS
This is the redacted and reformatted output of a brilliant discussion I had with fighter crews in early 2022. Some of the considerations match the conclusion I arrived to and used to put together the Simplified Timeline in 2019.
Having no background in anything related to military aviation, my modus operandi was rather simple:
- understand the kinetic properties of the AIM-54;
- calculate the MAR, at that time vs AIM-120 (common adversary during trainings, and one of the most effective missiles back then);
- calculate DOR to fit a second shot
The approach for DCS suggested by the crews instead takes a much deeper, yet perfectly understandable, approach. It splits the Timeline into a defensive and an offensive series of considerations, then merges them and adds with tactical observations.
A Timeline composed of two parts:
- offensive section;
- defensive section.
Each part may draw different considerations. The results are used to determine the Timeline.
|Assess threat capabilities: determine the range at which the hostile can be a threat based on the weapons at its disposal.||Adversary: Su-27 “Flanker”, shooting a R27ER.|
|The First Launch Opportunity (FLO) is assessed. It represents the start of the adversaries’ WEZ.||R27ER: 60” battery life.
Rule of thumb: 1nm every 2″, ~30nm. ±2nm FLO.
|Hostile’s F-Pole for is approximated as half of the range, and both aircraft crank.||F-Pole: 30nm / 2 = ~15 nm
Note that the R27ER can’t handle a crank at those ranges, but this assessment serves to stay out of its kinematics even with different geometry.
|Minimum Out Range (MOR)¹ is the adversary’s F-Pole ± 2nm. The goal of the MOR is defeating the FLO.
If the fighter goes Out at MOR, it still has room for recommit.
|MOR = 15nm + a couple of miles.
Thus 15nm / 18nm depending on how close we want to get.
|Minimum Abort Range (MAR) determination.
MAR keeps the fighter out of the threat’s stern WEZ.
|The example is applicable also at different distances: a 17nm shot won’t F-Pole at 15nm, but at about 8-9 nm. MAR prevents the crew to get this close.
In this case, it can be set to 10-13 nm. This value depends on factors such as the manoeuvrability of the fighter (how tight it can turn), the altitude, and so on.
|The offensive part relies on the specific tactic: launch and leave or launch and decide.||The missile range is mostly decided by the battery life rather than kinematics².
For example, an AIM-120 can get to 50nm, but kinematically, it may go farther.
|F-Pole is determined using the same rules of thumbs.||Assuming a crank, F-Pole = ~25 nm.|
|A-Pole is the activation range of the missile’s seeker. It is approximated as the F-Pole plus the missile seeker activation range (MSAR³).||Considering a 35nm shot, F-Pole = ~18 nm.
AIM-120 MSAR = 8 nm → A-Pole = 25 nm.
|“Out” considerations. The determined A-Pole suggests when the fighter can leave.
As a rule of thumb, the A-Pole starts to collapse a bit as the range decreases.
|A-Pole at 25nm gives plenty of room for a recommit. The next shot would be taken at 22nm (assuming great recommit mechanics).
Due to the collapse of the A-Pole, the second activation should be at close to 15-18nm.
¹ MOR – Minimum Out Range: Note that this definition changes between platforms and services (e.g. US Navy vs USAAF vs others).
² Presently, AIM-120 battery life is 100s, AIM-54 is 200s.
³ Note that this is not an “official” acronym. It is used here for simplicity’s sake.
Putting everything together, the timeline sees “detect and shoot” at 50nm, and missile times out at ~25nm. Even if the hostile shoots back at 30nm, there are still 8-10nm before any reaction is necessary besides crank.
These values also have to take into consideration the capability of the aircraft in use. With an F-16, shooting at 50nm is rather hard due to the characteristics of the radar. Therefore, shooting at, for example, 35nm is more feasible, but also more dangerous.
A 35nm shot sees a F-Pole at 18nm, which is close to when defending at MOR is considered.
If Minimum Out Range is missed, this is not a FLO launch, and it can be bypassed to MAR, if the MAR numbers allow.
The Desired Out Range (DOR) is really a number that is decided, assuming everything is done right, to allows recommitting with whatever criteria desired.
For example, if the initial shot is at 50nm, DOR may be set to 30nm. Since the missile should be active by then, and it completely negates the bandit’s shot (see examples above). This DOR value allows for two recommits, if done right.
The tactics should be defined depending on the goal, and then work the shots from there based on the missile’s kinematic characteristics.
For example, a first AIM-54 Phoenix shot can be 60nm because it allows more room before getting into the defensive. The kinematics are not really worse, and most of the time it is defeated by, assuming no things such as notching, chaff or track extrapolation issues, the target turning cold. Depending on tasking and mission, this can be a first win as a cold bandit is a non-factor until it turns around again, on top of wasting fuel and energy, losing awareness, and so on.
Comms and Leading the Flight/Element>
Issue: understanding the level of knowledge of the members of the flight. The Flight leader (#1) should be the person with higher level, the second should be the Element leader (#3).
The Intent is briefed only to the Element leader (#3), he makes sure that his Element follows the intent, going over the next steps and the parameters discussed. The less experienced Pilot (#4) won’t necessarily understand all, but he should remember:
- the MAR numbers;
- the MOR numbers;
- and the Shoot numbers.
Besides that, his task is to shoot the indicated target, and stay with his Element lead. It is the Element leader that updates geometry, and the wingman follows.
Other points to remark are, for example:
- how to take a good shot;
- make sure and how to crank;
- when you go out, and the out mechanics;
- when you recommit, and the recommit mechanics.
In other words, what he has to do with his fighter jet, to make tactics work. With time, practice and effort, this ensures that the less knowledgeable members become proficient.
“ok dude, set your radar up, slew it to the left, get your cursor out at 25 miles, make sure the elevation reads 10-30”
” in a minute we are going to turn hard left, I want you to roll out at heading XXX, and the first thing you see lock and shoot”
If the wingman is experienced and capable of following, the instructions would be as simple as:
“Hot Left, Target Group X”
The initial question is: “what make you decide between L&L and L&D?“. Or, from a different perspective, “why are you here?“.
For example, if the task is defending something for a specific amount of time, the default tactic is probably Launch and Leave, maximising the grind leafs and how much the fighters can “back pedal”, until they can’t back pedal any more, and then fully swap to maximum aggression and banzai, to clean up whatever is left before the can destroy the defended target. Or die trying.
Thus, the fundamental question becomes “what is more valuable“? The defended target or the fighter?
If the fighter is more valuable, then the aggression is increased to a level that maximises the risk. Id est, if the fighter is more important, then no banzai. Maybe only a short skate, or maybe only a banzai if the situation can be turned and numerical advantage is achieved.
If the target is more valuable, then the aggression can be smartly increased from less risky to more risky tactics. Eventually, in the short hairs, the fighters will banzai whatever is out there. “1v8? No problem! Let’s go and fight until the gun is dry“.
These considerations tie to the timeline: if the fighters are doing defensive tactics, the concern is about how many leafs are remaining, and trying to clean up things without having to banzai if unnecessary. Thus, fighters may have to pick lower PK shots to buy time because a target that turns is a target that is not getting closer, equals more time.
The trick is recognising when a picture allows swapping to more aggressive actions without buying too much risk.
For more offensive tactics, the risk can be reduced by taking more aggressive tactics early (i.e. banzai from the initial commit), and assess how that changes the situation if you are not necessarily defending.
In the timeline presented above, the fighters would still shoot at the max range assessed to be effective, the reason is, they can assess the effects of the shot before having to defend. In other words, if the missile launched at 50nm timeouts at 25nm, the fighters are not even threatened by an R27ER at that point. The hostile might have a missile in the air, but the fighters still have 8nm before having to consider defending.
Thus, the first set of missiles times out, perhaps killing 2 out of 4 threats. If that’s the case, the fighters can banzai to the merge, but before doing that, second round of missiles go in, so that as they cross the 10nm, the hostiles are either defending the second set of missiles, since in a single commit we got two shots in, or they are running very cold.
The situation now should be that either someone got very lucky and dodged 2-3 missiles, or the hostiles are either running away or have been hit.
The corollary is, that set a range, for example 25 nm, the fighters should assess at such distance that, if not bandits are dead, than that is an opportunity to immediately swap to a short skate, take the second set of missiles off, then go Out at first active indications or NLT MAR. At that point, let the dust settle, and figure out the plan from there, whether it is getting a follow on, or moving into more high-risk stuff like pitching elements back inside a stern WEZ, or trying to get separation and somebody unobserved.
If the fighters, in this banzai example, were to hold their shots waiting for a higher PK, they would lose the ability to get two rounds of shots in, before having to decide.
With an AIM-54 Phoenix, if the first shot is bumped up to 60-70 nm, the fighters may get two AIM-54s out and still have a 15nm AIM-7 Sparrow (or another Phoenix).
Another aspect, which is a DCSism, is to never expect a PK > 50%. Sometimes you do worse, sometimes you do better, but at the best of times this is the most you can expect.
If you build that PK assumption into your gameplan, it allows you to consider what happens when shots miss. Because they will.
Cover picture (or part of it) from Wikipedia.